I am making a multistage coilgun, with the switching of stages controlled by an Arduino Uno R3. There are ten stages total, and each stage has 5 80uf 330v photoflash capacitors. I need a way to switch that high voltage into the coils, and I have decided to use an Arduino to control that. The problem is, I don't have the money or time to use correctly rated relays, and wire them up to work with the Arduino. So I was looking at the relay boards sold for switching 120VAC, but the voltage I am switching is very far outside the rated voltage for the relays. Would it still work, at least in short term, or would it fry the relays instantly, or weld their contacts? any help is appreciated.
The relay board I am considering: http://www.ebay.com/itm/16-Channel-5V-Relay-Module-Optocoupler-Protection-Power-Supply-Arduino-PIC-DSP/252124532517?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D167e4df2b792461f8cfaff32c63a7e26%26pid%3D100338%26rk%3D1%26rkt%3D17%26sd%3D291440146340